Harmonic Drive Actuator R58 Module for Wrist/Head
Product Overview
The Balanced Choice for Mid-Size Joints
The CrabNova R58 occupies the sweet spot in the CrabNova lineup — delivering 20 Nm of continuous torque (45 Nm peak) at just 550 grams in its standard configuration. It's the actuator you reach for when the R48 doesn't have enough torque, but you still need to keep weight and size under control. With a 58mm outer diameter and a slim 65.2mm profile, it fits comfortably into human-scale wrist and compact elbow joints.
What distinguishes the R58 is its two-tier offering: a Standard version that maximizes power-to-weight for basic position/speed control applications, and an Upgraded version with an integrated torque sensor (±0.5% FS accuracy, 70 Nm range) that enables true force-controlled manipulation. The upgraded variant adds only 160g and 12mm in length while unlocking impedance control, force limiting, and contact detection — capabilities that transform a simple wrist actuator into a collaborative manipulation platform.
Both versions share the same core architecture: a 101:1 harmonic drive with 30 arcsec backlash, dual 19-bit absolute encoders, and a high-bandwidth drive running at 20 kHz current loop / 10 kHz speed loop. Triple protocol support — EtherCAT, CAN FD, and CANOpen — ensures compatibility with virtually any robot control architecture, from research platforms running open-source stacks to industrial controllers on deterministic fieldbuses.
🎯 Why the R58 Matters: The jump from R48 to R58 is the single most impactful upgrade in the CrabNova product line. You get 3× the torque for only 2× the weight, making it the highest torque-density module in the sub-kilogram class. For robot designers, this means you can spec the R58 for wrist joints with confidence that it won't be the bottleneck when payload requirements inevitably increase.
Technical Specifications
Complete Parameter List
Based on CrabNova product specifications. Both Standard and Upgraded variants shown.
⚙️ Mechanical Specifications
| Parameter | R58 Standard | R58 Upgraded | Notes |
|---|---|---|---|
| Model | CE-RB-R58-101-DNN-CO-I | CE-RB-R58-101-FNT-I | — |
| Reduction Ratio | 101:1 | Harmonic drive | |
| Rated Torque | 20 Nm | Continuous | |
| Peak Torque | 45 Nm | Transient | |
| Output Speed | 30 RPM | At rated load | |
| Backlash | 30 arcsec | Harmonic drive | |
⚡ Electrical Characteristics
| Parameter | R58 Standard | R58 Upgraded |
|---|---|---|
| Rated Voltage | 48V DC | |
| Rated Power | 168 W | 168 W |
| Rated Speed | 2500 RPM | |
| Rated Current | 3.5 A | |
| Peak Current | 10.8 A | |
📡 Control & Sensing
| Parameter | R58 Standard | R58 Upgraded |
|---|---|---|
| Encoder | Dual encoders, 19-bit absolute (524,288 counts/rev) | |
| Control Interface | EtherCAT / CAN FD / CANOpen | |
| Current Loop | 20 kHz | |
| Speed Loop | 10 kHz | |
| Brake | — | — |
| Torque Sensor | — | 70 Nm range, ±0.5% FS, RS485 |
📏 Physical Dimensions
| Parameter | R58 Standard | R58 Upgraded |
|---|---|---|
| Dimensions | R58 × 65.2 mm | R58 × 77.2 mm |
| Weight | 0.55 kg | 0.71 kg |
| Target Applications | Wrist roll/pitch, compact elbow, collaborative end-effectors | |
Key Features
Why the R58 Excels in Force-Sensitive Applications
⚡ 3× the Torque of R48, Only 2× the Weight
The R58 delivers 36 Nm/kg torque density (rated) — the highest in the sub-kilogram actuator class. 20 Nm continuous with 45 Nm peak handles wrist loads that would stall smaller modules, while the 550g standard weight keeps swing inertia low enough for responsive arm dynamics. This is the actuator that unblocks wrist joint design for humanoid robots carrying 3–5 kg payloads.
🎯 Integrated Torque Sensing (Upgraded)
The upgraded R58 variant incorporates a 70 Nm rated torque sensor with ±0.5% FS accuracy and 300% overload tolerance. RS485 digital output streams torque data directly to your controller — no external load cells or strain gauge amplifiers needed. This enables impedance control, gravity compensation, collision detection, and force-limited operation with a single integrated module. Release time ≤50 ms ensures responsive safety behavior.
🔌 Triple Protocol: EtherCAT + CAN FD + CANOpen
The R58 is the only actuator in its class offering all three major robot communication protocols. EtherCAT provides deterministic multi-axis control for industrial systems; CAN FD delivers high-bandwidth data for research platforms; CANOpen ensures compatibility with legacy controllers and open-source stacks. The 20 kHz current loop and 10 kHz speed loop provide ample bandwidth for advanced control algorithms regardless of your chosen bus.
🔧 Two Configurations, One Platform
Need pure torque-to-weight for a basic position-controlled wrist? Standard R58 at 550g. Need force feedback for collaborative manipulation? Upgraded R58 with integrated torque sensor at 710g. Same mounting pattern, same electrical interface, same control protocol — swap between variants as your application evolves without redesigning your mechanical integration.
Application Scenarios
Where the R58 Is the Right Choice
✋ Humanoid Wrist Joints
The R58's 20 Nm continuous torque is sized precisely for wrist roll and pitch on full-size humanoids handling 3–5 kg payloads. At 550g, it keeps the forearm's moment of inertia manageable while providing enough torque margin for dynamic manipulation. The Upgraded version's torque sensor enables compliant grasping — the hand yields when it contacts an obstacle rather than crushing it.
🤝 Collaborative Robot Arms
The Upgraded R58 with torque sensing is purpose-built for cobot joints requiring ISO/TS 15066 power-and-force-limiting compliance. The integrated torque sensor eliminates the need for external joint torque sensing, simplifying mechanical design. 45 Nm peak provides the transient torque needed for rapid collision response and emergency stops.
🔬 Research Platforms with Force Control
For robotics research labs exploring impedance control, admittance control, or reinforcement learning with force feedback, the Upgraded R58 provides a turnkey sensing solution. The RS485 torque sensor streams at controller bandwidth, and the CAN FD interface handles the combined telemetry of position, velocity, and torque without bottlenecking.
🔧 Precision Assembly End-Effectors
The Standard R58 at 550g is an excellent choice for compact rotary end-effectors — screwdriving spindles, nut runners, and precision alignment stages. The 20 Nm continuous torque handles most fastening operations, while 30 arcsec backlash ensures accurate angular positioning. EtherCAT compatibility integrates seamlessly with industrial automation controllers.
How to Choose: Standard vs. Upgraded
| Your Requirement | Recommended |
|---|---|
| Pure position/speed control — no force feedback needed | R58 Standard (0.55 kg) |
| Force-controlled manipulation, impedance control, or cobot safety | R58 Upgraded (0.71 kg) |
| Lowest possible weight is the priority | R58 Standard |
| Need collision detection or gravity compensation | R58 Upgraded |
What's Included
Package Contents
Every R58 order ships with everything needed for bench-top evaluation and integration.
| # | Item | Qty | Description |
|---|---|---|---|
| 1 | CrabNova R58 Actuator | 1 | Fully assembled, factory-calibrated (Standard or Upgraded) |
| 2 | Communication Cable Set | 1 set | EtherCAT/CAN FD/CANOpen interface cables |
| 3 | Power Cable | 1 | 48V DC power connection |
| 4 | Mounting Hardware | 1 set | Socket head screws for flange mounting |
| 5 | Product Datasheet | 1 | Technical specs, mechanical drawings, and pinout diagram |
| 6 | Software Access | — | JxServo Studio + CANopen/EtherCAT protocol documentation |
| 7 | Calibration Certificate | 1 | Per-unit factory calibration data (torque sensor for Upgraded) |
💻 Software & Resources: All CrabNova actuators are supported by JxServo Studio for configuration, tuning, and real-time telemetry. Full protocol documentation — including CANopen object dictionary, EtherCAT ESI files, and MIT impedance mode guide — at docs.juxieservo.com.
Why Buy from RobX
Sourced in China, Supported in California
When you buy a CrabNova R58 from RobX, you get more than a component. You get a partner who speaks your language — literally and technically.
US-Based PhD Technical Support
Your technical questions answered by a robotics PhD in California — in fluent English, during US business hours. We help with sizing, protocol selection, and torque sensor integration.
California Sample Inventory
Units stocked in California for immediate evaluation. Test in your lab within days — not weeks. No customs clearance, no freight forwarding.
DDP Pricing & Full Logistics
All pricing is DDP (Delivered Duty Paid). We handle export, freight, customs, and import duties. One invoice, one delivery.
Direct Manufacturer Relationship
As an authorized distributor of CrabNova (Juxie Intelligent Drive), we get priority allocation, direct engineering escalation, and advance notice of firmware and product updates.
